I changed all my fluids not too long ago when i bought this thing. Now when i did the t-case i was BARELY able to get one quart in it. Now i read that it takes 2 and a half quarts... HOW!? I think that might be why my 4x4 has stopped working? Hope it didnt burn it up. It worked before the change. Since then it hasnt. I filled the case till it was coming out of the full plug just like the front and rear diff. Is there another 3rd plug somewhere? Its a 99 3-button zr2. Whichever t-case that makes it. Let me know so i can call it by its proper name.

edit: also i put in the auto trac 2. dealer said thats what it takes. Starting to wonder if he was right.

 

Well.. After a fair amount of searching again. I finally came across what I think im looking for. It's a 233 new process. Which takes regular old ATF..

Could this be the soul problem why it wont shift into 4x4 anymore? It worked fine before the fluid change. Even worked for a few test runs in my back field in 4x4 after the change. But after a few weeks it wont do a thing.

 

I have never had a 233 so take this with a grain of salt


Yes the case does take dexron-III transmission fluid. I have heard to NOT use dexron-IV fluid. If it were me, I'd buy some generic fluid thats dexron-III compatible, but GM does license a product for transfercases that is just that. Either way I would change out the fluid ASAP. For capacity, I've read some places that it holds 2.2 pints which is just a smidge over a quart, so I don't see a problem there. If you verify it does hold two quarts, has the level decreased? If so you may have had it air-locked (happens with some boat lower units)

As for whether you did any damage and/or is that the reason for not shifting, I just don't know enough about the internal workings to say. I would switch it out for the proper fluid and see if your 4wd doesn't come back. If not, you may have to do some repair. But IMO it would still be wise to get the proper fluid in there.

 

From reading the 3 button t-case does take regular ATF. I have the 4 button t-case so I did use the auto-trac but mine did hold 2 quarts. From reading some I thought they all help around 2 quarts but maybe the ZR2's are different.

 

I drained out the old and put in the dex 3 stuff. Took it for a quick drive a few miles. Still nothing. Just unhooked battery for the half hour TCCM relearn. Maybe that will cure me. Not holding high hopes for that one though. With luck it will work. If not ill look for fuses. Though i do not thing thats my problem since its lighting up and clicking as if it has power... Next i guess is the vac lines. I hear a common one is the line going to the canister under the battery box. Guess that will be my first check if i have time before work later.

 

Autotrak 2 is overkill for the NV231/233, but won't hurt a thing. It has friction modifiers for the clutch in the NV236/NV136 & the BW AWD transfer cases, but nothing that would prohibit from lubricating the internal components inside the other t-cases.

Your problem is with one of the other components and likely is covered in one of the tech articles.